Negroni →
“The Negroni was created in Italy, likely in the early 1900s,” says bartender Dylan Knox of Vol. 39 in Chicago. “The story goes, Count Camillo Negroni asked a bartender to strengthen his favorite cocktail, the Americano—which called for using vermouth, Campari and club soda—and the Negroni was [born].” As they say, enjoying bitterness is an acquired taste. This colorful, bitter favorite is a classic aperitif cocktail recipe. I prefer 1 1/2 parts Gin to 1 Campari and 1 Sweet Vermouth and 3-4 drops of fresh orange juice to soften the bitterness of the Campari.
Source: https://www.liquor.com/recipes/negroni/#gs.f8n276